The analysis and field measurement of condensation risk by moisture generation on the enclosed balcony space

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1 IAQVEC 2016, 9th International Conference Indoor Air Quality Ventilation & Energy Conservation In Buildings The analysis and field measurement of condensation risk by moisture generation on the enclosed balcony space June Hae Lee 1, Ye Jin Kim 1, Chang Rae Lee 1, Myoung Souk Yeo 1 and Kwang Woo Kim 1 1 Seoul National University, Seoul, South Korea * Corresponding msyeo@snu.ac.kr ABSTRACT Balconies in Korean apartment is enclosed with external windows that this space function as a thermal buffer between outdoor and living area. The construction method of the balcony has chronologically changed by Korean residential regulation and lifestyle of the Korean tenant. The definition of the balcony area treated as outdoor space, however, the Korean residents has occupied this space as semi-living space. Confliction between regulation and space features, which causes the problem of condensation occurrence and leads to the mold growth on the surface of the walls to deteriorate the balcony environment. Applying an air ventilation solution is selected as a solution for the condensation risk on the surface wall of the balcony space. In order to apply proper air ventilation system for the balcony area, field measurement of the temperature and relative humidity change by the outdoor condition and relative humidity enter from the living space is necessary for understand the environmental condition during heating period in Korea. The setting condition of the temperature changes in balcony area depends on the thermal mass of the structure. But, the humidity rapidly changes by the opening to the indoor/ outdoor space. In this study, testify the temperature and relative humidity changes by the window opening and closing during the moisture activity by the field measurement. KEYWORDS Field Measurement, Enclosed balcony space, Condensation, Temperature and relative humidity, Ventilation INTRODUCTION The most vulnerable area for condensation risk among the apartment tenant s property is the balcony space. When the condensation lasts longer on the finishing surface of the balcony causes the mold growth in the space, which leads the damage to the building finishing material and makes the tenant s property area visually unpleasant space. While the other countries construct balcony as attached space for the building, many of balconies in Korea builds the window to distinguish the indoor and outdoor space. Visually enclosed balcony provides a great chance for the tenant to use or treat the balcony as an indoor space that there is a high possibility of condensation risk on the balcony area. This space division provides tenants the opportunity to use the space as storage, or additional indoor space that mostly used for laundry washing and drying room. Condensation on the balcony space causes the legal conflict between the tenant and construction company which is one of the social issues in South Korea. The resident believes condensation happens due to the mistreated construction by the construction company. The construction company insists that condensation occurs because of the living style of occupant produces the exceed amounts of moistures. The balcony is defined as an outdoor space in Korean architecture law that the construction company doesn t have an obligation to construct

2 the balcony wall with insulation panels to keep the space as thermally similar condition as indoor living space. According to the precedence study of the classification of balconies by orientation and usability, it is proven that the balcony next to the kitchen is a highest possible place for condensation risk. In this study analysis the temperature and relative humidity changes of the enclosed balcony space, which is located next to the kitchen, during and after moisture generation inside of the space to understand the environmental condition of the balcony space and condensation risk on the surface. METHODS The experimental field measurement was taken during the heating period season that the outdoor temperature was average 4ºC and the setup indoor space temperature as 22ºC. Sensors located in the north east facing balcony at the empty unit which was a newly built apartment that construction was completed in October 2015, located in Incheon, Korea. This balcony space was designed to function as an additional kitchen that has a place for laundry washing machine and the extra kitchen sink. Since the place was empty unit without the washing machine and water from the tub was not working, the experiment was taken with a humidifier to generate the moisture for imitating the space as water usage place. The space condition was measured with temperature and relative humidity sensor. Figure 1 shows the temperature and relative humidity sensor location. Four sensors measured the air temperature and relative humidity, and 14 sensors measured the surface walls at the balcony space. The sensor was collecting the data during the afternoon, night, and morning with two different cases that the control object was balcony window opening and humidifier on/off (Table 1). a) b) Figure 1. Temperature and relative humidity sensor location. a) Sensor location with floor plan, b) Install of surface temperature sensor Table 1. Experimental Measurement Case Condition Humidifier Window Balcony Door Afternoon (2:00-4:00PM) Period Night (8:00-10:00PM) Morning (9:00-11:00AM) Case 1 On Closed Closed 30min 30min 30min After Case 2 Off Closed Closed 30min 30min 30min Case 2 On Open Closed 30min 30min 45min After Case 2 Off Closed Closed 30min 30min 15min

3 FIELD MEASUREMENT RESULTS Temperature and Relative Humidity Changes Figure 2 shows the temperature and relative humidity changes during the different condition while the measurement is taken during the night time (8:00-10:00 PM). The average relative humidity at the indoor space stays around 40%, the balcony space RH changes from 49% to 95% of the whole experiment cases. Case 1 result shows that the RH increased during the experimental period. RH at the lower part of the balcony area raised higher than the upper part of space and the sensor located near the window shows the lowest RH among the balcony space RH. Case 2 was taken while the window was open to the outdoor that the RH at balcony area fluctuated to balance out the outdoor RH. Since the moist air tries to layer down at the lower level, the lower part of the balcony area shows the higher RH values. The balcony was not designed for a thermal comfort zone and a concrete wall constructed without insulation panel. The temperature at the balcony shows average 12ºC which is between outdoor (Avg. 4ºC) and kitchen (Avg. 22ºC) space temperature. The temperature at the upper part of the space increased sharply when a person enters the balcony area for control the moisture condition. The temperature changes affected by the buoyancy that the lower part of balcony area and window area temperature remains low. During case 2 the window as open for 30min but the temperature of the space have not drop down as similar as outdoor temperature because the influence of the thermal mass of the concrete wall structure. a) b) Figure 2. Field measurement results during night time. a) RH changes, b) Temperature changes. Surface Temperature differences with Dew point Temperature The surface temperature examines with the dew point temperature whether the possibility of condensation risk. The dew point temperature near humidifier (no. 5), the lower part of balcony space (no.6), Upper part of balcony space (no.8), near window space (no. 9) with the surface around have been investigated closely (Figure3). Figure4 shows the surface temperature location 9 and 8 resulted in the highest possibility to cause the condensation risk based on the dew point temperature location at no. 5 sensor. The point 9 located near the humidifier and the point 8 located where balcony floor and wall which divides the balcony and air conditioning plant room. Since air conditioning plant room is open to the outdoor place that recorded as lowest temperature place among the unit. And the wall between this space and balcony space is only working for space division, and there are no thermal breaks. The point 7 and 10 is the surface of the shaft that not directly meet the outdoor

4 lower temperature condition. Surface 10 recorded safely higher temperature because the shaft is located the inner place of unit property. Figure 5 represents that dew point temperature at the lower part of balcony space shown that the cause the higher possibility of condensation risk during the case 1 and after case 1. However, ventilation with opening the window reduce the condensation risk near around lower part of the balcony space. The floor surface temperature (no. 14) shows higher temperature compare with the temperature location no.8. The floor temperature is affected the below level unit temperature. However the heat loss from the air condition plant room is higher than heat loss to the below level unit. Figure 6 shows that the surface temperature of no.4 and no. 6 is lower than the dew point temperature of upper part of the space. A no.4 sensor located at the point where the surface window wall and ceiling meets, and no. 6 sensor located at the meeting point of shaft wall and ceiling. Not only has the thermal mass of the concrete wall but also the window openings affected the surface temperature heat loss at the point no. 4. As shown in the result of figure 7, near window area surface has a low possibility of the condensation risk. Case 2 and after case 2 indicates that the dewpoint temperature decrease due to the percentage of the RH decreased. Even the window is a closed case; moist air moves out the from the leakage gap at the installed window. a) b) c) d) Figure 3. Dew point temperature location and surface temperature location. a) Near humidifier, b) Lower part of the balcony, c) Upper part of balcony, d) Near window.

5 Figure 4. Surface temperature comparison with Dew point temperature at no. 5 location Figure 5. Surface temperature comparison with Dew point temperature at no. 6 location

6 Figure 6. Surface temperature comparison with Dew point temperature at no. 8 location Figure 7. Surface temperature comparison with Dew point temperature at no. 9 location DISCUSSIONS AND CONCLUSIONS In this study analysis the temperature and relative humidity changes of the enclosed balcony space, which is located next to the kitchen, during and after moisture generation inside of the space to understand the environmental condition of the balcony space and condensation risk on the surface. The results show that the condensation risk can be increased by the thermal mass of the wall and space types or condition beyond the wall. The surface temperature point where the floor and surface wall divide the space between air conditioning plant room shows most vulnerable location for condensation risk. While surface wall separated with the conditioned space and inner shaft space recorded higher temperature and condensation risk-

7 free. Therefore, the plant room temperature drops down almost low as outdoor temperature that it requires to be constructed with insulation panel for anti-condensation. The further ventilation solution has to be experimented and developed for the anti-condensation at the balcony space. Comparing the experimental case 1 and case 2 results show that when moisture generated inside of the balcony space, the condensation risk was safe on the surface walls. Therefore, it is suggested to tenants to open the windows for ventilation while using the space for moisture generation activity. Since the moist air located at the lower part of the balcony space and the condensation risk at the below level is higher compares to the upperlevel space, the ventilation requires to located at the lower level. However, the opening duration and size need to be a further study for not to lowering the temperature inside the space. ACKNOWLEDGEMENT This research was supported by a grant(16rerp-b ) from Residential Environment Research Program funded by Ministry of Land, Infrastructure and Transport of the Korean government. REFERENCES Kim Y.S., Kim J.G., and Lee B.H A Study on the Measures to Prevent Condensation through State of the Condensation in Apartment Balcony, Conference of Architectural Institute of Korea, Park C.S Emerging from Customary Design for Balcony Space in Apartment. Journal of Architectural Institute of Korea 20.4, Salonvaara M., Tuomo O., and Achilles K Indoor air humidity variations and its effects on the moisture performance of building envelope. Eighth International IBPSA Conference. Vol